Pipe wrench with spring-biased hook-jaw



United States Patent PIPE WRENCH WITH SPRING-BIASED HOOK-JAW Karol T. Dyczynski, Erie, Pa., assignor to Eric Tool Works, Erie, Pa., a corporation of Pennsylvania Application June 30, 1953, Serial No. 364,990

3 Claims. (Cl. 81101) In pipe wrenches it is desirable that the movable or hook jaw be spring biased to the open position. This invention is intended to provide such a wrench with a biasing spring which can be easily assembled and which will not fall out even if the hook jaw is disassembled.

In the accompanying drawing, Fig. l is a side elevation of a wrench, Fig. 2 is a sectional elevation, Fig. 3 is a section on line 33 of Fig. 1 with the hook jaw and spring removed, and Figs. 4 and 5 are fragmentary sections of modifications.

The conventional parts of the wrench are readily identified, 1 being the housing having a stationary jaw 2 riveted thereto, 3 being an aperture in the housing receiving the threaded shank 4 of a hook jaw 5, and 6 being retaining lugs for a nut 7 which adjusts the hook jaw. On the side of the housing opposite the jaws is a fiat projection 8 which is useful in tapping unions to jar the threads loose. The parts so far described are or may be of common construction and are subject to substantial differences in construction and appearance.

Under turning load, the pipe gripping action is obtained by a rocking movement of the hook jaw to the left as viewed in Figs. 1, 2, and in order that the hook jaw can be normally held in position to rock into the gripping position springs have been used to urge the hook jaw to the right or rearward. Since plumbers frequently have to work in cramped spaces, it has been considered important that the biasing spring remain in place even if the hook jaw is accidentally removed because the spring might be lost if it fell out. In the present wrenches, the housing has a cored out recess 9 intermediate the ends of the aperture 3 and on the side toward the front of the stationary jaw. At the mouth 10 of the recess and extending crosswise between the side walls 11 is a pin 12 (Fig. 2), a rib 12a at the end of a cast web 12b (Fig. 4) or integral projections 12c cast on the inner surface of the walls 11 and extending toward each other (Fig. 5). The pin 12, the rib 12a and the projections 120 all serve the same purpose and function as locking or retaining projections fitting in reentrant portions or depressions 13 adjacent the vertex portions 14 of folded strip spring steel springs 15 (Fig. 2), 15a (Fig. 4), or 15b (Fig. 5). The apexes of the depressions 13 extend toward the front wall 17 of the recess 9 and the depressions are located on the sides of the vertex portions 14 facing the shank. The spring 15 has a single fold with a leaf 16 engaging the front wall 17 of the recess 9 and a leaf 18 engaging the shank 4 and urging it to the right. The pin 12 confines leaf 18 between it and the front wall of the recess but does not prevent movement of the leaf toward the front wall of the recess which may take place when the hook jaw rocks to the left or forward under load. The spring 15a has a double fold, there being a leaf 16a engaging the front wall 17 of the recess 9, a leaf 18a engaging the shank 4, and a leaf 19 between the rib 12a and the leaf 16a. The rib 12a, like the pin 12, confines the leaf 18;: between it and the front wall of the recess but does not prevent movement of the leaf toward the front wall of the recess which may take place when the hook jaw rocks to the left. The spring 15b is a triple fold spring, there being a leaf 16b engaging the front wall 17 of the recess 9, a leaf 20 engaging the shank 4 and urging it to the right or rearward, and two intermediate leaves 18b and 1%. From one aspect, the additional folds in the spring 1512 merely provide greater effective length of leaves on opposite sides of the vertex portion 14 so that a greater deflection can be had without overstressing the spring. The leaf 18b is confined between the projection 12c and the front wall of the recess but is free to deflect inward under load.

Each of the springs 15, 15a, 15b is assembled in the same manner by first inserting a spring through the upper end of the aperture 3 and by then pushing the vertex portion 14 under one of the locking projections 12, 12a, until the projection snaps into reentrant portion 13. Each spring thus assembled is releasably held in place independent of the presence of the shank 4 on the hook jaw. In all of the springs, the locking projections prevent movement of the springs out of the recess but do not interfere with deflection of the springs into the recess under load.

What is claimed as new is:

1. In a wrench, a frame having a handle, a stationary jaw, and an aperture at the back end of the stationary jaw, a recess in the frame intermediate the ends of the aperture on the side toward the front of the stationary jaw and having a front wall, a hook jaw having a threaded shank extending through the aperture, a folded strip spring having spaced leaves, at least two leaves having a vertex portion between the leaves, one of the spaced leaves engaging the front wall of the recess in the frame and another of the spaced leaves engaging the shank outside the recess and exerting a rearward pressure on the shank, and a projection in the recess spaced from an end of the vertex portion and the front wall of the recess and engaging a side of the vertex portion remote from the front wall of the recess to confine the vertex portion between the projecting and the front wall of the recess.

2. The construction of claim 1 in which the side of the vertex portion engaging the projection has a reentrant depression into which the projection fits.

3. The construction of claim 1 in which the leaf engaging the shank is separate from and in addition to the two leaves having said vertex portion between the projection and the bottom of the recess.

References Cited in the file of this patent UNITED STATES PATENTS 509,408 Torkelson Nov. 28, 1893 2,650,512 Johnson et a1. Sept. 1, 1953 

